https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106591
Bug ID: 106591
Summary: ASan at -O1 fails to detect a global buffer overflow
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
For the following code, `gcc-trunk -O1 -fsanitize=address` failed to detect the
global-buffer-overflow, while other opt flags (-O0, -O2, and -O3) can.
$cat a.c
a;
*b = &a, *d = &a;
volatile static **c = &b;
int foo(int p1, int p2) {
return p1 % p2;
}
static int* e() {
**c;
int *f = &a;
return f + 1;
}
int main() {
*c = e();
*d = 1;
foo(**c, *d);
}
$
$gcc-trunk -O1 -fsanitize=address -w -g && ./a.out
$
$gcc-trunk -O2 -fsanitize=address -w -g && ./a.out
=================================================================
==1==ERROR: AddressSanitizer: global-buffer-overflow on address 0x000000404224
at pc 0x00000040113b bp 0x7ffff3ecdca0 sp 0x7ffff3ecdc98
READ of size 4 at 0x000000404224 thread T0
#0 0x40113a in main /app/a.c:16
#1 0x7f68868750b2 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x240b2) (BuildId:
9fdb74e7b217d06c93172a8243f8547f947ee6d1)
#2 0x4011ad in _start (/app/output.s+0x4011ad) (BuildId:
db3aa359dc97f1881309f971535063412033e172)
0x000000404224 is located 0 bytes to the right of global variable 'a' defined
in '/app/a.c:1:1' (0x404220) of size 4
SUMMARY: AddressSanitizer: global-buffer-overflow /app/a.c:16 in main
Shadow bytes around the buggy address:
0x0000800787f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078810: 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
0x000080078820: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 f9
0x000080078830: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
=>0x000080078840: 00 00 00 00[04]f9 f9 f9 f9 f9 f9 f9 00 00 00 00
0x000080078850: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078860: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078870: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078890: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==1==ABORTING
